140 lines
3.7 KiB
C
140 lines
3.7 KiB
C
/* $OpenBSD: uvm_io.c,v 1.30 2022/10/07 14:59:39 deraadt Exp $ */
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/* $NetBSD: uvm_io.c,v 1.12 2000/06/27 17:29:23 mrg Exp $ */
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/*
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* Copyright (c) 1997 Charles D. Cranor and Washington University.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* from: Id: uvm_io.c,v 1.1.2.2 1997/12/30 12:02:00 mrg Exp
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*/
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/*
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* uvm_io.c: uvm i/o ops
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mman.h>
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#include <sys/uio.h>
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#include <uvm/uvm.h>
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/*
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* functions
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*/
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/*
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* uvm_io: perform I/O on a map
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*
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* => caller must have a reference to "map" so that it doesn't go away
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* while we are working.
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*/
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int
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uvm_io(vm_map_t map, struct uio *uio, int flags)
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{
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vaddr_t baseva, endva, pageoffset, kva;
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vsize_t chunksz, togo, sz;
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struct uvm_map_deadq dead_entries;
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int error, extractflags;
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/*
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* step 0: sanity checks and set up for copy loop. start with a
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* large chunk size. if we have trouble finding vm space we will
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* reduce it.
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*/
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if (uio->uio_resid == 0)
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return(0);
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togo = uio->uio_resid;
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baseva = (vaddr_t) uio->uio_offset;
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endva = baseva + (togo - 1);
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if (endva < baseva) /* wrap around? */
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return(EIO);
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if (baseva >= VM_MAXUSER_ADDRESS)
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return(0);
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if (endva >= VM_MAXUSER_ADDRESS)
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/* EOF truncate */
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togo = togo - (endva - VM_MAXUSER_ADDRESS + 1);
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pageoffset = baseva & PAGE_MASK;
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baseva = trunc_page(baseva);
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chunksz = min(round_page(togo + pageoffset), MAXBSIZE);
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error = 0;
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extractflags = 0;
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if (flags & UVM_IO_FIXPROT)
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extractflags |= UVM_EXTRACT_FIXPROT;
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/*
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* step 1: main loop... while we've got data to move
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*/
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for (/*null*/; togo > 0 ; pageoffset = 0) {
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/*
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* step 2: extract mappings from the map into kernel_map
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*/
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error = uvm_map_extract(map, baseva, chunksz, &kva,
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extractflags);
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if (error) {
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/* retry with a smaller chunk... */
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if (error == ENOMEM && chunksz > PAGE_SIZE) {
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chunksz = trunc_page(chunksz / 2);
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if (chunksz < PAGE_SIZE)
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chunksz = PAGE_SIZE;
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continue;
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}
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break;
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}
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/*
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* step 3: move a chunk of data
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*/
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sz = chunksz - pageoffset;
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if (sz > togo)
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sz = togo;
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error = uiomove((caddr_t) (kva + pageoffset), sz, uio);
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togo -= sz;
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baseva += chunksz;
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/*
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* step 4: unmap the area of kernel memory
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*/
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vm_map_lock(kernel_map);
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TAILQ_INIT(&dead_entries);
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uvm_unmap_remove(kernel_map, kva, kva+chunksz,
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&dead_entries, FALSE, TRUE, FALSE);
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vm_map_unlock(kernel_map);
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uvm_unmap_detach(&dead_entries, AMAP_REFALL);
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if (error)
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break;
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}
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return (error);
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}
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